/Engine/Plugins/Animation/IKRig/Source/IKRigEditor/Public/RigEditor/IKRigController.h
Set the root bone on a given solver. (not all solvers support root bones, checks CanSetRootBone() first)
[UFUNCTION](Programming/UnrealArchitecture/Reference/Functions)(BlueprintCallable, BlueprintPure=false, Category=IKRig) bool SetRootBone ( const [FName](API\Runtime\Core\UObject\FName) RootBoneName, int32 SolverIndex ) const